The charger has to signal that it is capable of providing more than the standard current. There are two ways this can be done - one is via the USB standard, an

The charger has to signal that it is capable of providing more than the standard current. There are two ways this can be done - one is via the USB standard, and the other is the Apple way. Needless to say most chargers go the Apple way, so you should generally look for chargers that claim to not be compatible with Apple. Here is an example story of trying to find one: https://plus.google.com/117091380454742934025/posts/5suTrJrpbHF https://plus.google.com/117091380454742934025/posts/5suTrJrp... In some cases the chargers and devices have gone a third way. This is very typical for tablets as they need a lot more current in order to charge within a reasonable time frame. At that point many manufacturers have made up their own way of signalling the ability.